Primary Hyperparathyroidism - PDF Free Download

Primary Hyperparathyroidism In primary hyperparathyroidism (PHPT), an enlargement of one or more of the parathyroid glands causes overproduc7on of the parathyroid hormone. This hormone regulates the level of calcium in the body, including the release of calcium from bones and the excre7on of calcium in the urine. It also increases calcium absorp7on in the duodenum by changing 25(OH)D to the ac7ve form of vitamin D: 1,25(OH)2D. Abnormally high parathyroid hormone levels typically result in hypercalcemia. The most common cause of PHPT is parathyroid adenoma, found in 80% of pa7ents. Hyperplasia is involved in most other cases, and carcinoma is a rare cause. Na7onal Ins7tute of Diabetes and Diges7ve and Kidney Diseases. Primary Hyperparathyroidism. Available at hxps://www.niddk.nih.gov/health-informa7on/endocrine-diseases/primary-hyperparathyroidism. Accessed August 28, 2018. Mayo Clinic. Hyperparathyroidism. Available at hxps://www.mayoclinic.org/diseases-condi7ons/hyperparathyroidism/symptoms-causes/syc-20356194. Accessed August 28, 2018. Velez RP et al. Simplifying the Complexity of Primary Hyperparathyroidism. The Journal for Nurse Prac55oners 2016; 12(5): 346 352. Copyright 2019 American Associa7on of Clinical Endocrinologists 2

Epidemiology of PHPT In the United States, primary hyperparathyroidism is the most common cause of hypercalcemia encountered in ambulatory care. About 100,000 people develop PHPT each year. It is diagnosed most ohen in people between age 50 and 60, and women are affected two to three 7mes more ohen than men. Postmenopausal women have the highest incidence. Na7onal Ins7tute of Diabetes and Diges7ve and Kidney Diseases. Primary Hyperparathyroidism. Available at hpps://www.niddk.nih.gov/health-informa7on/endocrinediseases/primary-hyperparathyroidism. Accessed August 28, 2018. Velez RP et al. Simplifying the Complexity of Primary Hyperparathyroidism. The Journal for Nurse Prac55oners 2016; 12(5): 346 352. Copyright 2019 American Associa7on of Clinical Endocrinologists 3

Clinical Presenta-on One of the most common manifesta7ons of PHPT is nephrolithiasis. In the United States, 15% to 20% of pa7ents with PHPT present with kidney stones, due to high calcium levels in the glomerular filtrate. However, in addi7on to maintaining bone health, calcium plays a role in metabolic processes, nerve impulse conduc7on, muscle contrac7on, and the clonng cascade. Abnormally elevated calcium can affect the nervous, renal, cardiac, and gastrointes7nal systems. Khan AA et al. Primary hyperparathyroidism: review and recommenda7ons on evalua7on, diagnosis, and management. A Canadian and interna7onal consensus. Osteoporosis Interna-onal 2017; 28 (1):1 19 Wilhelm SM et al. The American Associa7on of Endocrine Surgeons Guidelines for Defini7ve Management of Primary Hyperparathyroidism. JAMA Surg 2016;151(10):959-968. Velez RP et al. Simplifying the Complexity of Primary Hyperparathyroidism. The Journal for Nurse Prac--oners 2016; 12(5): 346 352. Copyright 2019 American Associa7on of Clinical Endocrinologists 4

Clinical Presenta-on, Con-nued Pa7ents may therefore present with other renal, musculoskeletal, gastrointes7nal, and psychiatric symptoms. ( Stones, bones, abdominal groans, psychiatric moans. ) These include: Anorexia Nausea/vomi7ng Cons7pa7on Insomnia Depression Fa7gue/muscle weakness Arthri7s Bone and/or joint pain Bone demineraliza7on/ fractures Polydipsia and polyuria Interna-onal 2017; 28 (1):1 19 Velez RP et al. Simplifying the Complexity of Primary Hyperparathyroidism. The Journal for Nurse Prac--oners 2016; 12(5): 346 352. Copyright 2019 American Associa7on of Clinical Endocrinologists 5

Clinical Presenta-on, Con-nued Such symptoms are typically seen in pa7ents whose calcium levels rise rapidly. If calcium levels increase slowly, pa7ents may adapt to the change and have no symptoms. In resource rich countries, as many as 85% of pa7ents with PHPT may be asymptoma7c. In addi7on, some pa7ents with mild PHPT may have high levels of parathyroid hormone but normal levels of calcium (normocalcemic hyperparathyroidism). Interna-onal 2017; 28 (1):1 19 Velez RP et al. Simplifying the Complexity of Primary Hyperparathyroidism. The Journal for Nurse Prac--oners 2016; 12(5): 346 352. Copyright 2019 American Associa7on of Clinical Endocrinologists 6

Diagnosing PHPT Hypercalcemia in conjunc7on with abnormally elevated or inappropriately normal parathyroid hormone levels makes PHPT the most likely diagnosis. Calcium and parathyroid hormone levels should be tested at the same 7me because individual levels fluctuate quickly. Hypercalcemic pa7ents may occasionally have normal calcium levels, so repeated calcium measurements may be required. Measurement of serum calcium should be adjusted for albumin, as 40% of calcium is bound to serum proteins, predominantly albumin. If the adjusted serum calcium is normal but parathyroid hormone is elevated, serum ionized calcium should be measured. PHPT can present with an elevated ionized calcium despite a normal albumin-adjusted serum calcium. Interna-onal 2017; 28 (1):1 19 Velez RP et al. Simplifying the Complexity of Primary Hyperparathyroidism. The Journal for Nurse Prac--oners 2016; 12(5): 346 352. Copyright 2019 American Associa7on of Clinical Endocrinologists 7

Diagnosing Normocalcemic PHPT Pa7ents with normocalcemic PHPT will have elevated parathyroid hormone but normal levels of serum and ionized calcium. To establish a diagnosis of normocalcemic PHPT, secondary causes of elevated parathyroid hormone should be excluded, such as primary hypercalciuria, malabsorp7on syndromes, use of loop diure7cs, bisphosphonates, or denosumab therapy. In addi7on, renal func7on and vitamin D status should be assessed with measurements of crea7nine and 25-hydroxyvitamin D. Elevated serum parathyroid hormone with consistently normal albumin-adjusted calcium and ionized calcium, normal serum 25-hydroxyvitamin D, and wellmaintained renal func7on (egfr >60 ml/min/1.73 m 2 ) supports the diagnosis of normocalcemic PHPT. Normocalcemic PHPT may progress to classic PHPT over 7me. Interna-onal 2017; 28 (1):1 19 Velez RP et al. Simplifying the Complexity of Primary Hyperparathyroidism. The Journal for Nurse Prac--oners 2016; 12(5): 346 352. Copyright 2019 American Associa7on of Clinical Endocrinologists 8

Ruling Out Familial Hypocalciuric Hypercalcemia Familial hypocalciuric hypercalcemia (FHH), an autosomal dominant disorder of the renal calcium-sensing receptor, can mimic PHPT. A 24-hour urinary calcium level is important to dis7nguish PHPT from FHH. A diagnosis of FHH should be considered in pa7ents with long-standing hypercalcemia, urinary calcium levels less than 100mg/24 hours, and a calcium-to-crea7nine clearance ra7o less than 0.01. Copyright 2019 American Associa7on of Clinical Endocrinologists 9

Addi$onal Tests PHPT reduces bone mineral density and may increase the risk for fragility fractures. Dual-energy x-ray absorp7ometry assessment is appropriate for all pa7ents with PHPT and should be performed to screen for weakened bones and skeletal problems. Bone mineral density should be measured at the lumbar spine, hip, and distal radius. The 24-hour urine calcium test is also recommended. In pa7ents with asymptoma7c PHPT, abdominal imaging may be useful for detec7ng nephrocalcinosis or nephrolithiasis. Interna-onal 2017; 28 (1):1 19 Velez RP et al. Simplifying the Complexity of Primary Hyperparathyroidism. The Journal for Nurse Prac--oners 2016; 12(5): 346 352. Copyright 2019 American Associa7on of Clinical Endocrinologists 10

Treatment: Surgery Surgery to remove abnormal parathyroid 7ssue is the only known cure for PHPT. Symptoma7c pa7ents with PHPT should be advised to undergo surgery. Surgery is also recommended for asymptoma7c pa7ents with the following indica7ons: Age < 50 years Serum calcium > 1 mg/dl (> 0.25 mmol/l) above upper limit of normal Bone mineral density T-score of 2.5 (osteoporosis) or a low-energy fracture on imaging study Crea7nine clearance reduced to < 60 ml/min, or 24-hour urine for calcium > 400 mg/day and increased stone risk by biochemical stone risk analysis, or nephrolithiasis or nephrocalcinosis on imaging study Even when there is no specific indica7on for surgery, it is an established and appropriate treatment because it is the only known cure. Interna-onal 2017; 28 (1):1 19 Velez RP et al. Simplifying the Complexity of Primary Hyperparathyroidism. The Journal for Nurse Prac--oners 2016; 12(5): 346 352. Copyright 2019 American Associa7on of Clinical Endocrinologists 11

Treatment: Surgery Minimally invasive parathyroid (MIP) surgery to remove abnormal glands has become the standard of care. With an experienced surgeon, cure rates with minimally invasive procedures exceed 95%, and the complica7on rate is low (1% to 3%). A general or local anesthesia is used, and pa7ents can usually be discharged home 2 hours aler surgery. Pa7ents who require extensive neck explora7on or excision of all four glands may require open surgery. Parathyroid hormone (PTH) monitoring during surgery can confirm the removal of all hyperfunc7oning parathyroid glands, as the half-life of the hormone is 3-5 minutes. If the PTH level decreases by at least 50 % and falls into the normal range following resec7on, this confirms that adequate 7ssue has been resected and that no further explora7on is necessary. When an image-guided focused parathyroidectomy is planned, intraopera7ve PTH monitoring is recommended to avoid missing mul7-gland disease. Surgery has been shown to normalize calcium and parathyroid hormone levels, reduce the risk of kidney stones, and improve bone remodeling and skeletal health. It may also have other cardiovascular, renal, neurological, and gastrointes7nal benefits. Interna-onal 2017; 28 (1):1 19 Velez RP et al. Simplifying the Complexity of Primary Hyperparathyroidism. The Journal for Nurse Prac--oners 2016; 12(5): 346 352. Copyright 2019 American Associa7on of Clinical Endocrinologists 12

Treatment: Repeat Surgery Repeat surgery may be necessary in up to 5% of pa7ents who develop persistent PHPT due to incomplete resec7on of abnormal parathyroid 7ssue. In addi7on, up to 8% of pa7ents will develop recurrent disease within 3 to 11 years and require repeat surgery. In pa7ents with persistent PHPT, a diagnosis of familial hypocalciuric hypercalcemia (FHH) should be considered and ruled out before repeat surgery. Interna-onal 2017; 28 (1):1 19 Copyright 2019 American Associa7on of Clinical Endocrinologists 13

When Surgery Is Not an Op3on Surgery is not recommended in pa7ents for whom the risks outweigh the benefits, such as those with severe or overriding medical illnesses. In addi7on, some pa7ents will refuse surgery. Other situa7ons that may prompt nonsurgical management include: First trimester pregnancy Severely limited cervical access Prior vocal cord paralysis Short expected lifespan Interna3onal 2017; 28 (1):1 19 Copyright 2019 American Associa7on of Clinical Endocrinologists 14

Monitoring Non-Surgical Pa1ents For pa7ents who refuse surgery or in whom it is contraindicated, monitoring can be a safe op7on for up to 8-10 years. Bone mineral density tests should be performed ever 1-2 years in these pa7ents. Biochemical profiles should be assessed yearly. In addi7on, calcium intake should be recommended without restric7ons according to the Ins7tute of Medicine Guidelines, and vitamin D levels should be sufficient. Finally, although medical management cannot cure PHPT, it can be an op7on for non-surgical pa7ents. Interna3onal 2017; 28 (1):1 19 Copyright 2019 American Associa7on of Clinical Endocrinologists 15

Medical Management Currently, the only medica7on shown to lower serum calcium in pa7ents with PHPT is the calcimime7c agent cinacalcet. Cinacalcet normalizes serum calcium in 70% to 80% of pa7ents with PHPT. However, it has not been shown to impact bone mineral density, hypercalcemic symptoms, kidney stones, or quality of life. Close monitoring of serum calcium levels is necessary in pa7ents on cinacalcet because of its adverse effects on QT prolonga7on, arrhythmias, heart failure, and hypotension. Marcocci C et al. Medical management of primary hyperparathyroidism: proceedings of the fourth Interna7onal Workshop on the Management of Asymptoma7c Primary Hyperparathyroidism. J Clin Endocrinol Metab 2014; 99(10): 3607-18. Interna5onal 2017; 28 (1):1 19 Copyright 2019 American Associa7on of Clinical Endocrinologists 16

Medical Management Bisphosphonates may be used in combina7on with cinacalcet in pa7ents with T-scores 2.5 at the lumbar spine, hip, or one-third radius, or who have fragility fractures. These agents have been shown to be effec7ve in preven7ng decreases in bone mineral density and lowering bone remodeling. Many pa7ents with PHPT will have vitamin D deficiency or insufficiency. Normalizing vitamin D is recommended. It has been shown to reduce serum parathyroid hormone levels without increasing serum calcium. Marcocci C et al. Medical management of primary hyperparathyroidism: proceedings of the fourth Interna7onal Workshop on the Management of Asymptoma7c Primary Hyperparathyroidism. J Clin Endocrinol Metab 2014; 99(10): 3607-18. Interna5onal 2017; 28 (1):1 19 Copyright 2019 American Associa7on of Clinical Endocrinologists 17